-/*

- Copyright (c) 2008 TrueCrypt Developers Association. All rights reserved.

-

- Governed by the TrueCrypt License 3.0 the full text of which is contained in

- the file License.txt included in TrueCrypt binary and source code distribution

- packages.

-*/

-

-#include "Platform/Memory.h"

-#include "Common/Crc.h"

-#include "Common/Endian.h"

-#include "EncryptionModeCBC.h"

-

-namespace VeraCrypt

-{

- void EncryptionModeCBC::Decrypt (byte *data, uint64 length) const

- {

- if_debug (ValidateState ());

- if_debug (ValidateParameters (data, length));

-

- if (IsOuterCBC (Ciphers))

- {

- DecryptBuffer (data, length, Ciphers, (uint32 *) IV.Ptr(), (uint32 *) (IV.Ptr() + WhiteningIVOffset));

- }

- else

- {

- for (CipherList::const_reverse_iterator iCipherList = Ciphers.rbegin();

- iCipherList != Ciphers.rend();

- ++iCipherList)

- {

- CipherList cl;

- cl.push_back (*iCipherList);

-

- DecryptBuffer (data, length, cl, (uint32 *) IV.Ptr(), (uint32 *) (IV.Ptr() + WhiteningIVOffset));

- }

- }

- }

-

- void EncryptionModeCBC::DecryptBuffer (byte *data, uint64 length, const CipherList &ciphers, const uint32 *iv, const uint32 *whitening) const

- {

- size_t blockSize = ciphers.front()->GetBlockSize();

- if (blockSize != 8 && blockSize != 16)

- throw ParameterIncorrect (SRC_POS);

-

- uint32 *data32 = (uint32 *) data;

- uint32 bufIV[4];

- uint32 ct[4];

- uint64 i;

-

- bufIV[0] = iv[0];

- bufIV[1] = iv[1];

- if (blockSize == 16)

- {

- bufIV[2] = iv[2];

- bufIV[3] = iv[3];

- }

-

- for (i = 0; i < length / blockSize; i++)

- {

- // Dewhitening

- data32[0] ^= whitening[0];

- data32[1] ^= whitening[1];

- if (blockSize == 16)

- {

- data32[2] ^= whitening[0];

- data32[3] ^= whitening[1];

- }

-

- // CBC

- ct[0] = data32[0];

- ct[1] = data32[1];

- if (blockSize == 16)

- {

- ct[2] = data32[2];

- ct[3] = data32[3];

- }

-

- for (CipherList::const_reverse_iterator iCipherList = ciphers.rbegin();

- iCipherList != ciphers.rend();

- ++iCipherList)

- {

- const Cipher &c = **iCipherList;

-

- if (c.GetBlockSize () != blockSize)

- throw ParameterIncorrect (SRC_POS);

-

- c.DecryptBlock ((byte *) data32);

- }

-

- // CBC

- data32[0] ^= bufIV[0];

- data32[1] ^= bufIV[1];

- bufIV[0] = ct[0];

- bufIV[1] = ct[1];

- if (blockSize == 16)

- {

- data32[2] ^= bufIV[2];

- data32[3] ^= bufIV[3];

- bufIV[2] = ct[2];

- bufIV[3] = ct[3];

- }

-

- data32 += blockSize / sizeof(*data32);

- }

-

- Memory::Erase (bufIV, sizeof (bufIV));

- Memory::Erase (ct, sizeof (ct));

- }

-

- void EncryptionModeCBC::DecryptSectorsCurrentThread (byte *data, uint64 sectorIndex, uint64 sectorCount, size_t sectorSize) const

- {

- if_debug (ValidateState ());

- if_debug (ValidateParameters (data, sectorCount, sectorSize));

-

- uint32 sectorIV[4];

- uint32 sectorWhitening[2];

-

- while (sectorCount--)

- {

- if (IsOuterCBC (Ciphers))

- {

- InitSectorIVAndWhitening (sectorIndex, Ciphers.front()->GetBlockSize(), (uint64 *) IV.Ptr(), sectorIV, sectorWhitening);

- DecryptBuffer (data, sectorSize, Ciphers, sectorIV, sectorWhitening);

- }

- else

- {

- for (CipherList::const_reverse_iterator iCipherList = Ciphers.rbegin();

- iCipherList != Ciphers.rend();

- ++iCipherList)

- {

- const Cipher &c = **iCipherList;

- CipherList cl;

- cl.push_back (*iCipherList);

-

- InitSectorIVAndWhitening (sectorIndex, c.GetBlockSize(), (uint64 *) IV.Ptr(), sectorIV, sectorWhitening);

- DecryptBuffer (data, sectorSize, cl, sectorIV, sectorWhitening);

- }

- }

-

- data += sectorSize;

- sectorIndex++;

- }

-

- Memory::Erase (sectorIV, sizeof (sectorIV));

- Memory::Erase (sectorWhitening, sizeof (sectorWhitening));

- }

-

- void EncryptionModeCBC::Encrypt (byte *data, uint64 length) const

- {

- if_debug (ValidateState ());

- if_debug (ValidateParameters (data, length));

-

- if (IsOuterCBC (Ciphers))

- {

- EncryptBuffer (data, length, Ciphers, (uint32 *) IV.Ptr(), (uint32 *) (IV.Ptr() + WhiteningIVOffset));

- }

- else

- {

- for (CipherList::const_iterator iCipherList = Ciphers.begin();

- iCipherList != Ciphers.end();

- ++iCipherList)

- {

- CipherList cl;

- cl.push_back (*iCipherList);

-

- EncryptBuffer (data, length, cl, (uint32 *) IV.Ptr(), (uint32 *) (IV.Ptr() + WhiteningIVOffset));

- }

- }

- }

-

- void EncryptionModeCBC::EncryptBuffer (byte *data, uint64 length, const CipherList &ciphers, const uint32 *iv, const uint32 *whitening) const

- {

- size_t blockSize = ciphers.front()->GetBlockSize();

- if (blockSize != 8 && blockSize != 16)

- throw ParameterIncorrect (SRC_POS);

-

- uint32 *data32 = (uint32 *) data;

- uint32 bufIV[4];

- uint64 i;

-

- bufIV[0] = iv[0];

- bufIV[1] = iv[1];

- if (blockSize == 16)

- {

- bufIV[2] = iv[2];

- bufIV[3] = iv[3];

- }

-

- for (i = 0; i < length / blockSize; i++)

- {

- data32[0] ^= bufIV[0];

- data32[1] ^= bufIV[1];

- if (blockSize == 16)

- {

- data32[2] ^= bufIV[2];

- data32[3] ^= bufIV[3];

- }

-

- for (CipherList::const_iterator iCipherList = ciphers.begin();

- iCipherList != ciphers.end();

- ++iCipherList)

- {

- const Cipher &c = **iCipherList;

-

- if (c.GetBlockSize () != blockSize)

- throw ParameterIncorrect (SRC_POS);

-

- c.EncryptBlock ((byte *) data32);

- }

-

- bufIV[0] = data32[0];

- bufIV[1] = data32[1];

- if (blockSize == 16)

- {

- bufIV[2] = data32[2];

- bufIV[3] = data32[3];

- }

-

- data32[0] ^= whitening[0];

- data32[1] ^= whitening[1];

- if (blockSize == 16)

- {

- data32[2] ^= whitening[0];

- data32[3] ^= whitening[1];

- }

-

- data32 += blockSize / sizeof(*data32);

- }

-

- Memory::Erase (bufIV, sizeof (bufIV));

- }

-

- void EncryptionModeCBC::EncryptSectorsCurrentThread (byte *data, uint64 sectorIndex, uint64 sectorCount, size_t sectorSize) const

- {

- if_debug (ValidateState ());

- if_debug (ValidateParameters (data, sectorCount, sectorSize));

-

- uint32 sectorIV[4];

- uint32 sectorWhitening[2];

-

- while (sectorCount--)

- {

- if (IsOuterCBC (Ciphers))

- {

- InitSectorIVAndWhitening (sectorIndex, Ciphers.front()->GetBlockSize(), (uint64 *) IV.Ptr(), sectorIV, sectorWhitening);

- EncryptBuffer (data, sectorSize, Ciphers, sectorIV, sectorWhitening);

- }

- else

- {

- for (CipherList::const_iterator iCipherList = Ciphers.begin();

- iCipherList != Ciphers.end();

- ++iCipherList)

- {

- const Cipher &c = **iCipherList;

- CipherList cl;

- cl.push_back (*iCipherList);

-

- InitSectorIVAndWhitening (sectorIndex, c.GetBlockSize(), (uint64 *) IV.Ptr(), sectorIV, sectorWhitening);

- EncryptBuffer (data, sectorSize, cl, sectorIV, sectorWhitening);

- }

- }

-

- data += sectorSize;

- sectorIndex++;

- }

-

- Memory::Erase (sectorIV, sizeof (sectorIV));

- Memory::Erase (sectorWhitening, sizeof (sectorWhitening));

- }

-

- void EncryptionModeCBC::InitSectorIVAndWhitening (uint64 sectorIndex, size_t blockSize, const uint64 *ivSeed, uint32 *iv, uint32 *whitening) const

- {

- if (blockSize != 8 && blockSize != 16)

- throw ParameterIncorrect (SRC_POS);

-

- uint64 iv64[4];

- uint32 *iv32 = (uint32 *) iv64;

-

- iv64[0] = ivSeed[0] ^ Endian::Little (sectorIndex);

- iv64[1] = ivSeed[1] ^ Endian::Little (sectorIndex);

- iv64[2] = ivSeed[2] ^ Endian::Little (sectorIndex);

- if (blockSize == 16)

- {

- iv64[3] = ivSeed[3] ^ Endian::Little (sectorIndex);

- }

-

- iv[0] = iv32[0];

- iv[1] = iv32[1];

-

- if (blockSize == 8)

- {

- whitening[0] = Endian::Little ( crc32int ( &iv32[2] ) ^ crc32int ( &iv32[5] ) );

- whitening[1] = Endian::Little ( crc32int ( &iv32[3] ) ^ crc32int ( &iv32[4] ) );

- }

- else

- {

- iv[2] = iv32[2];

- iv[3] = iv32[3];

-

- whitening[0] = Endian::Little ( crc32int ( &iv32[4] ) ^ crc32int ( &iv32[7] ) );

- whitening[1] = Endian::Little ( crc32int ( &iv32[5] ) ^ crc32int ( &iv32[6] ) );

- }

- }

-

- bool EncryptionModeCBC::IsOuterCBC (const CipherList &ciphers) const

- {

- if (ciphers.size() < 2)

- return false;

-

- size_t blockSize = ciphers.front()->GetBlockSize();

-

- for (CipherList::const_iterator iCipherList = ciphers.begin();

- iCipherList != ciphers.end();

- ++iCipherList)

- {

- const Cipher &c = **iCipherList;

- if (c.GetBlockSize() != blockSize)

- return false;

- }

-

- return true;

- }

-

- void EncryptionModeCBC::SetKey (const ConstBufferPtr &key)

- {

- if (key.Size() != GetKeySize ())

- throw ParameterIncorrect (SRC_POS);

-

- if (!KeySet)

- IV.Allocate (GetKeySize ());

-

- IV.CopyFrom (key);

- KeySet = true;

- }

-}